Explaining Pain Dr. Erik Pohlman, PT, DPT

Pain is a common problem! 1 in 6 Americans live with persistent pain1 Globally, 20% have pain > 3 months2 Persistent pain costs ~$100 billion/yr3

Definition of Pain Pain is an “unpleasant sensory and emotional experience associated with actual or potential tissue damage.”4 International Association for the Study of Pain (IASP) Pic found at http://poweroverpain.blogspot.com/

Old Model Painful stimulus→PAIN Tissue damage = pain Descartes proposed a direct wiring mechanism of pain in 1644

How do we explain… Phantom limb pain Painless battle wounds even in those born without the limb5 Painless battle wounds Papercut hurting so much

Other Examples WWII vet – bullet in neck 60 years, he never knew!6 Surfers – feel a ‘bump,’ no more leg!

These patients had no pain, weakness, or sensation changes!7

Also have evidence of people with “bone on bone” OA with no pain. These examples illustrate the fact that the experience of pain is not perfectly linked with actual bodily harm or damage. 8

Will this hurt? Of course… Pain is normal and is there to protect us from injury.

How about now? Why?

Threat Initially, the body only had to worry about the nail Nail→Threat→PAIN When you are running from the lion, the nail is the least of your worries Nail→Lion is bigger threat→Nail doesn’t hurt Explains soldiers in battle More on this later…

Threat It is the perception of the threat that determines the output, not the tissue damage itself or threat to the tissues…8 Pain = Output

So how does pain really work? It is a complex system with many contributors.

Nociceptors (“Pain sensors”) Mechanical, Temperature, and Chemical They tell the brain ‘danger’, NOT ‘pain’ Brain determines if you should feel pain Body can add or subtract all over the body Replaced as often as every few days Current levels of sensitivity can and will change! Remember that we don’t have to have damage to have pain, but it is important to know a little about the sensors that can send such signals to the brain.

Sensitization Increased sensitivity after injury Allodynia, hyperalgesia Normal, but should fade after healing Persists in people with chronic pain

Central Sensitization2 The spinal cord and brain cells are more sensitive You may notice: Pain longer than normal tissue healing time Spreading pain Worsening pain Even small movements hurt Pain is unpredictable (what hurts one day may not hurt the next, or thinking about it can cause pain) You have other significant ‘threats’ in your life

Homuncu-what?

Homunculus Map of body in the brain Phantom limb ‘Smudging’ in chronic pain and phantom pain More chronic -> more smudging9 So fixing a mechanical issue, like a disc, doesn’t always fix the real problem.

Neuroplasticity Not to worry! The brain and nervous system are constantly changing Braille users10 and guitarists/violinists/cellists11

Brain Centers Not just 1 center or one input (like from the tissues) Neurotag – many parts of the brain activating in a unique pattern2 Sensory, motor, memory, emotion, autonomic nervous system, etc. All parts light up in phantom pain But there isn’t just 1 center in the brain responsible for pain. Each pain experience is unique and consists of a unique pattern of activation ALL OVER THE BRAIN. Danger signal, on its own, is NOT enough to produce pain!

Pain relies on context Perception of threat level modifies pain according to the situation Finger injury in professional violinist vs. dancer12 Whiplash from car accident An important part of these networks is the brain’s memory of previous situations and its thoughts on what the injury means to the individual. Explain car accident in depth, looking up and R was how we got hurt, brain says, so don’t do that.

Thought Viruses Thoughts are nerve signals too Ever feel pain when thinking about the painful movement or watching someone else do it? Anxiety about pain or disability can increase pain We have proven through multiple studies that pain education, relaxation, etc can reduce pain experiences, sometimes more than drugs, core stabilization, and other treatments.

HURT ≠ HARM What does this tell us? Pain comes from the brain, not muscle, tendon, disc, etc and… HURT ≠ HARM

How can we fix our pain?

Bed rest? NO WAY!!! Blood flow leads to healing and less pain Re-define that ‘fuzzy’ section in brain Prevent atrophy

Surgery Last resort, or when rapidly progressing neuro symptoms Costly Risky Infection, nerve damage, Still have a recovery period May still not help Plenty of people who still have their pain after surgery

Medication Pain killers, anti-inflammatories, muscle relaxers, etc. May or may not help symptoms Often won’t help the actual cause

You are already well on your way! Pain education Patients can understand pain theories13 Knowing pain physiology reduces threat level14 …reducing sympathetic, endocrine, and motor activity.15,16 Combining pain physiology education and movement therapies improves physical capacity, reduces pain, and improves quality of life!17 Evidence shows that pain education may even be better at preventing pain than core stabilization18

Caution! Don’t get hung up on anatomy! Knowing more about pain leads to better results than knowing more about anatomy (bones, discs, alignment, etc)14 You have now learned that is one (possible) part in the pain experience

Tone down that nervous system Active Relaxation Deep breathing Breathing with diaphragm Heat, ice, TENS, anything else that works for you

Graded exposure Gradually increasing exercise, activity, and stimulation (desensitization) Re-teaches body/brain that movements and stimulation are ok Can also gradually re-expose yourself to driving or the thing you were doing when originally injured

Trick your nervous system Same movement, different context Do the movement in a different way Change the position or what moves first, do in water, etc.

See your friendly local physical therapist to… Rule out more serious issues and refer you to the proper provider if one is found Determine if there is a mechanical cause Provide more pain education Provide treatments like manipulation, dry needling, therapeutic movement/exercise, etc.

Points to remember Your pain is REAL Imaging (Xray, MRI) may be misleading Bedrest and waiting for it to improve will likely not help and may make it worse Motion is Lotion Pain is normal and it’s ok to feel some pain with exercise if you have chronic pain already HURT ≠ HARM See your physical therapist!!!

(Strongly) Recommended Reading Explain Pain, by David Butler

Thank you!

References 1. Chronic Pain elective, Regis University 2011, quoted this as coming from the ‘American Chronic Pain Association.’ 2. Butler D, Moseley GL. Explain Pain. Adelaide: NOI Group Publishing, 2003. 3. Chronic Pain elective, Regis University 2011, quoted this as coming from the ‘American Alliance of Cancer Pain Initiatives.’ 4. www.iasp-pain.org 5. Saadah ES, Melzack R. Phantom limb experiences in congenital limb deficient adults. Cortex. 1994;30(3):479-485. 6. The Times, Feb 17 2003, p 5, London. 7. Boden SD, et al. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. J Bone Joint Surg Am. 1990;72a(3):403-408. 8. Moseley GL. Reconceptualising pain according to modern pain science. Phys Ther Reviews. 2007;12:169-178. 9. Flor H, et al. Extensive reorganisation of primary somatosensory cortex in chronic back pain patients. Neurosci Letters. 1997;244:5-8. 10. Pascual-Leone A, Torres F. Plasticity of the sensorimotor cortex representation of the reading finger of braille readers. Brain. 1993;116:39-52. 11. Elbert TC, et al. Increased cortical representation of the fingers of the left hand in string players. Science. 1995;270:305-307. 12. Moseley GL. Joining forces- combining cognition-targeted motor control training with group or individual pain physiology education: a successful treatment for chronic low back pain. J Man Manip Ther. 2003;11:88-94. 13. Moseley GL. Unravelling the barriers to reconceptualisation of the problem in chronic pain: the actual and perceived ability of patients and health professionals to understand neurophysiology. J Pain. 2003;4:184-189. 14. Moseley GL, Hodges PW, Nicholas MK. A randomized controlled trial of intensive neurophysiology education in chronic low back pain. Clin J Pain. 2003;20(5):324-330. 15. Melzack R. Pain and stress: a new perspective in psychosocial factors in pain. RJ Gatchel and DC Turk. 1999, Guildford Press: New York. 16. Moseley GL. Evidence for a direct relationship between cognitive and physical change during an education intervention in people with chronic low back pain. Euro J Pain. 2004;8:39-45. 17. Moseley GL. Physiotherapy is effective for chronic low back pain: a randomised controlled trial. Aus J Physioth. 2002;48:297-302. 18. George SZ, Wittmer VT, Fillingim RB, Robinson ME. Comparison of graded exercise and graded exposure clinical outcomes for patients with chronic low back pain. JOSPT. 2010;40(11).